So they haven't found all the bodies yet and we have a probable cause. Don't know whay there is an NTSB then, just call pprune.
To add a little data. The PT-6 was originally designed as a stationary power unit for water pumping in very hot dry foreign places. In it's aviation use it is a reverse flow turbing, that is, it takes air in toward the lower rear of the engine and then the air flows foward to the first stage compressor. There is a huge amound of centrifical separation that occurs and tends to shed rocks, bolts, and other FOD before it gets into the engine. How anything but massive fire hosing of water would get through this I don't know. Please don't compare PT-6 to T-56, Orpheus, and other stuff like that. The TF-34 on the S-3 aircraft has a phenomenol reliability record and is maintained as has been previously suggested with frest water washdowns etc.
In many installations (Beech King Air etc) of the PT-6 the engine oil provides the power for the prop pitch control so if the engine fails in a mode that results in oil pressure or quantity loss the prop feathers.
Sympathy to the Chalk organization, pax and families. It is bad enough to get it like that, but to have lots of holiday pics on CNN of it...must be horible for the families.